.\" Copyright (c) 1997 Wolfgang Helbig
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.\" modification, are permitted provided that the following conditions
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.\" $FreeBSD: head/usr.bin/ncal/ncal.1 359418 2020-03-29 04:14:57Z grog $
.\"
.Dd March 7, 2019
.Dt CAL 1
.Os
.Sh NAME
.Nm cal ,
.Nm ncal
.Nd displays a calendar and the date of Easter
.Sh SYNOPSIS
.Nm
.Op Fl 3hjy
.Op Fl A Ar number
.Op Fl B Ar number
.Oo
.Op Ar month
.Ar year
.Oc
.Nm
.Op Fl 3hj
.Op Fl A Ar number
.Op Fl B Ar number
.Fl m Ar month
.Op Ar year
.Nm ncal
.Op Fl 3bhjJpwySM
.Op Fl A Ar number
.Op Fl B Ar number
.Op Fl W Ar number
.Op Fl s Ar country_code
.Oo
.Op Ar month
.Ar year
.Oc
.Nm ncal
.Op Fl Jeo
.Op Fl A Ar number
.Op Fl B Ar number
.Op Ar year
.Nm ncal
.Op Fl CN
.Op Fl H Ar yyyy-mm-dd
.Op Fl d Ar yyyy-mm
.Sh DESCRIPTION
The
.Nm
utility displays a simple calendar in traditional format and
.Nm ncal
offers an alternative layout, more options and the date of Easter.
The new format is a little cramped but it makes a year fit
on a 25x80 terminal.
If arguments are not specified,
the current month is displayed.
.Pp
The options are as follows:
.Bl -tag -width indent
.It Fl h
Turns off highlighting of today.
.It Fl J
Display Julian Calendar, if combined with the
.Fl o
option, display date of Orthodox Easter according to the Julian Calendar.
.It Fl e
Display date of Easter (for western churches).
.It Fl j
Display Julian days (days one-based, numbered from January 1).
.It Fl m Ar month
Display the specified
.Ar month .
If
.Ar month
is specified as a decimal number, appending
.Ql f
or
.Ql p
displays the same month of the following or previous year respectively.
.It Fl o
Display date of Orthodox Easter (Greek and Russian
Orthodox Churches).
.It Fl p
Print the country codes and switching days from Julian to Gregorian
Calendar as they are assumed by
.Nm ncal .
The country code as determined from the local environment is marked
with an asterisk.
.It Fl s Ar country_code
Assume the switch from Julian to Gregorian Calendar at the date
associated with the
.Ar country_code .
If not specified,
.Nm ncal
tries to guess the switch date from the local environment or
falls back to September 2, 1752.
This was when Great
Britain and her colonies switched to the Gregorian Calendar.
.It Fl w
Print the number of the week below each week column.
.It Fl y
Display a calendar for the specified year. This option is implied when
a year but no month are specified on the command line.
.It Fl 3
Display the previous, current and next month surrounding today.
.It Fl 1
Display only the current month. This is the default. 
.It Fl A Ar number
Months to add after. The specified number of months is added to the
end of the display. This is in addition to any date range selected by the
.Fl y ,
.Fl 3 ,
or
.Fl 1
options. For example,
.Dq Li cal -y -B2 -A2
shows everything from November of the previous year to
February of the following year. Negative numbers are allowed, in which
case the specified number of months is subtracted. For example, 
.Dq Li cal -y -B-6 
shows July to December. And 
.Dq Li cal -A11
simply shows the next 12 months.
.It Fl B Ar number
Months to add before. The specified number of months is added to the 
beginning of the display. See
.Fl A
for examples.
.It Fl C
Completely switch to
.Nm cal
mode. For
.Nm cal
like output only, use
.Fl b
instead.
.It Fl d Ar yyyy-mm
Use
.Ar yyyy-mm
as the current date (for debugging of date selection).
.It Fl H Ar yyyy-mm-dd
Use
.Ar yyyy-mm-dd
as the current date (for debugging of highlighting).
.It Fl M
Weeks start on Monday.
.It Fl S
Weeks start on Sunday.
.It Fl W Ar number
First week of the year has at least
.Ar number
days.
.It Fl b
Use oldstyle format for ncal output.
.El
.Pp
A single parameter specifies the year (1\(en9999) to be displayed;
note the year must be fully specified:
.Dq Li cal 89
will
.Em not
display a calendar for 1989.
Two parameters denote the month and
year; the month is either a number between 1 and 12, or a full or
abbreviated name as specified by the current locale.
Month and
year default to those of the current system clock and time zone (so
.Dq Li cal -m 8
will display a calendar for the month of August in the current
year).
.Pp
Not all options can be used together.
For example the options 
.Fl y , 3 , 
and 
.Fl 1 
are mutually exclusive. If inconsistent options are given, the later
ones take precedence over the earlier ones.
.Pp
A year starts on January 1.
.Pp
Highlighting of dates is disabled if stdout is not a tty.
.Sh SEE ALSO
.Xr calendar 3 ,
.Xr strftime 3
.Sh STANDARDS
The
.Nm
utility is compliant with the
X/Open System Interfaces option of the
.St -p1003.1-2008
specification.
.Pp
The flags
.Op Fl 3hyJeopw ,
as well as the ability to specify a month name as a single argument,
are extensions to that specification.
.Pp
The week number computed by
.Fl w
is compliant with the
.St -iso8601
specification.
.Sh HISTORY
A
.Nm
command appeared in
.At v1 .
The
.Nm ncal
command appeared in
.Fx 2.2.6 .
The output of the
.Nm cal
command is supposed to be bit for bit compatible to the original Unix
.Nm cal
command, because its output is processed by other programs like CGI scripts,
that should not be broken. Therefore it will always output 8 lines, even if
only 7 contain data. This extra blank line also appears with the original
.Nm cal
command, at least on Solaris 8
.Sh AUTHORS
The
.Nm ncal
command and manual were written by
.An Wolfgang Helbig Aq Mt helbig@FreeBSD.org .
.Sh BUGS
The assignment of Julian\(enGregorian switching dates to country
codes is historically naive for many countries.
.Pp
Not all options are compatible and using them in different orders
will give varying results.
.Pp
It is not possible to display Monday as the first day of the week with
.Nm cal .
